Depending on what your going for you can try out optimizepress or instabuilder.

Optimizepress is a wordpress theme used to create awesome landing pages/squeeze pages like a pro. Not really not a whole lot to it if you take the time to do it right the first time.

Now instabuilder is a plugin for wordpresss that allows you to create the same thing but with it's own twist. Again if you take your time and do it right the first time, (watch tutorials) then there shouldn't be a problem setting up anything.

In the event you somehow get stuck then let me know and I do my best to help you out when time permits. Hope this helps you and any others out.

In my opinion you don`t need to use wordpress to create legit landing page for 1 niche.
For example themeforest html themes are cheap, amazing desinged and easy to customize so you can use 1 theme with most of niches.